1. Technical Field
The present disclosure relates generally to surgical stapling instruments. More specifically, the present disclosure relates to circular surgical stapling instruments with stretchable bushings.
2. Background of Related Art
Surgical stapling instruments configured to join tissue during a surgical procedure are well known. These devices include linear end effectors which are oriented either parallel or transverse to a longitudinal axis of the instrument. Typically, circular stapling instruments include a cartridge or shell assembly that is fixedly attached to a distal end of the instrument and a detachable anvil moveably supported in relation to the shell assembly. Circular stapling instruments also include an anvil retainer that extends through the shell assembly and is coupled to the anvil to facilitate movement of the anvil towards the shell assembly and to clamp tissue between the shell assembly and the anvil. As the anvil is approximated in relation to the shell assembly, the coupling between the anvil and the anvil retainer may disengage in response to tension on the anvil. Typically, a bushing is provided to prevent disengagement of the coupling between the anvil and the anvil retainer. As the bushing is engaged, frictional forces between the bushing and the anvil retainer and/or the anvil increases such that the force required to approximate the anvil towards the shell assembly is increased.
A need exists for a coupling mechanism for a circular stapling instrument that reduces the frictional forces required to prevent disengagement of the coupling between the anvil and the anvil retainer.